1 README for GAS 2 3A number of things have changed since version 1 and the wonderful 4world of gas looks very different. There's still a lot of irrelevant 5garbage lying around that will be cleaned up in time. Documentation 6is scarce, as are logs of the changes made since the last gas release. 7My apologies, and I'll try to get something useful. 8 9Unpacking and Installation - Summary 10==================================== 11 12See ../binutils/README. 13 14To build just the assembler, make the target all-gas. 15 16Documentation 17============= 18 19The GAS release includes texinfo source for its manual, which can be processed 20into `info' or `dvi' forms. 21 22The DVI form is suitable for printing or displaying; the commands for doing 23this vary from system to system. On many systems, `lpr -d' will print a DVI 24file. On others, you may need to run a program such as `dvips' to convert the 25DVI file into a form your system can print. 26 27If you wish to build the DVI file, you will need to have TeX installed on your 28system. You can rebuild it by typing: 29 30 cd gas/doc 31 make as.dvi 32 33The Info form is viewable with the GNU Emacs `info' subsystem, or the 34stand-alone `info' program, available as part of the GNU Texinfo distribution. 35To build the info files, you will need the `makeinfo' program. Type: 36 37 cd gas/doc 38 make info 39 40Specifying names for hosts and targets 41====================================== 42 43 The specifications used for hosts and targets in the `configure' 44script are based on a three-part naming scheme, but some short 45predefined aliases are also supported. The full naming scheme encodes 46three pieces of information in the following pattern: 47 48 ARCHITECTURE-VENDOR-OS 49 50 For example, you can use the alias `sun4' as a HOST argument or in a 51`--target=TARGET' option. The equivalent full name is 52`sparc-sun-sunos4'. 53 54 The `configure' script accompanying GAS does not provide any query 55facility to list all supported host and target names or aliases. 56`configure' calls the Bourne shell script `config.sub' to map 57abbreviations to full names; you can read the script, if you wish, or 58you can use it to test your guesses on abbreviations--for example: 59 60 % sh config.sub i386v 61 i386-unknown-sysv 62 % sh config.sub i786v 63 Invalid configuration `i786v': machine `i786v' not recognized 64 65 66`configure' options 67=================== 68 69 Here is a summary of the `configure' options and arguments that are 70most often useful for building GAS. `configure' also has several other 71options not listed here. 72 73 configure [--help] 74 [--prefix=DIR] 75 [--srcdir=PATH] 76 [--host=HOST] 77 [--target=TARGET] 78 [--with-OPTION] 79 [--enable-OPTION] 80 81You may introduce options with a single `-' rather than `--' if you 82prefer; but you may abbreviate option names if you use `--'. 83 84`--help' 85 Print a summary of the options to `configure', and exit. 86 87`-prefix=DIR' 88 Configure the source to install programs and files under directory 89 `DIR'. 90 91`--srcdir=PATH' 92 Look for the package's source code in directory DIR. Usually 93 `configure' can determine that directory automatically. 94 95`--host=HOST' 96 Configure GAS to run on the specified HOST. Normally the 97 configure script can figure this out automatically. 98 99 There is no convenient way to generate a list of all available 100 hosts. 101 102`--target=TARGET' 103 Configure GAS for cross-assembling programs for the specified 104 TARGET. Without this option, GAS is configured to assemble .o files 105 that run on the same machine (HOST) as GAS itself. 106 107 There is no convenient way to generate a list of all available 108 targets. 109 110`--enable-OPTION' 111 These flags tell the program or library being configured to 112 configure itself differently from the default for the specified 113 host/target combination. See below for a list of `--enable' 114 options recognized in the gas distribution. 115 116`configure' accepts other options, for compatibility with configuring 117other GNU tools recursively; but these are the only options that affect 118GAS or its supporting libraries. 119 120The `--enable' options recognized by software in the gas distribution are: 121 122`--enable-targets=...' 123 This causes one or more specified configurations to be added to those for 124 which BFD support is compiled. Currently gas cannot use any format other 125 than its compiled-in default, so this option is not very useful. 126 127`--enable-bfd-assembler' 128 This causes the assembler to use the new code being merged into it to use 129 BFD data structures internally, and use BFD for writing object files. 130 For most targets, this isn't supported yet. For most targets where it has 131 been done, it's already the default. So generally you won't need to use 132 this option. 133 134Compiler Support Hacks 135====================== 136 137On a few targets, the assembler has been modified to support a feature 138that is potentially useful when assembling compiler output, but which 139may confuse assembly language programmers. If assembler encounters a 140.word pseudo-op of the form symbol1-symbol2 (the difference of two 141symbols), and the difference of those two symbols will not fit in 16 142bits, the assembler will create a branch around a long jump to 143symbol1, and insert this into the output directly before the next 144label: The .word will (instead of containing garbage, or giving an 145error message) contain (the address of the long jump)-symbol2. This 146allows the assembler to assemble jump tables that jump to locations 147very far away into code that works properly. If the next label is 148more than 32K away from the .word, you lose (silently); RMS claims 149this will never happen. If the -K option is given, you will get a 150warning message when this happens. 151 152 153REPORTING BUGS IN GAS 154===================== 155 156Bugs in gas should be reported to: 157 158 bug-binutils@gnu.org. 159 160They may be cross-posted to gcc-bugs@gnu.org if they affect the use of 161gas with gcc. They should not be reported just to gcc-bugs, since not 162all of the maintainers read that list. 163 164See ../binutils/README for what we need in a bug report. 165 166Copyright (C) 2012-2021 Free Software Foundation, Inc. 167 168Copying and distribution of this file, with or without modification, 169are permitted in any medium without royalty provided the copyright 170notice and this notice are preserved. 171